From: Edward Monk (emonk@xxxxxxx)
Date: Mon Aug 26 2002 - 15:07:53 GMT-3
Dmitry,
I think some of the confusion that you are encountered is that the
setting of the CIR to the AR of 96Kbps in the frame-relay map class
which is fine.
But when the calculations are done the error happens because you used
the CIR of 96Kbps that is set to the AR in the frame-relay map class.
The actual CIR for the calculations should be 64Kbps which is the SLA
CIR.
So the calculations all work out just fine. For the time intervals and
the byte limits that were quoted by Steve and Jim.
Time interval=Tc=Bc/CIR in seconds = 8000/64000 = .125
Byte increment= Cir*Tc/8= 64000*.125/8=1000 bytes = 8000 bits
Byte Limit= 1000+32000/8 =5000 bytes = 40000 bits
The CCO document that you linked to agrees with this. That's were I
actually pulled the equations from to check the CCO document accuracy.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Jim Brown
Sent: Monday, August 26, 2002 10:39 AM
To: 'Volkov, Dmitry (Toronto - BCE)'; 'steven.j.nelson@bt.com'; Jim
Brown; kip.palmer@verizon.net
Cc: ccielab@groupstudy.com
Subject: RE: I need FRTS help or review
Dmitry,
The original proposed scenario was a 96Kbps access/port speed and a
provider
contracted CIR of 64Kbps.
The use of BE also marks the DE bit of any packets above the CIR.
-----Original Message-----
From: Volkov, Dmitry (Toronto - BCE) [mailto:dmitry_volkov@ca.ml.com]
Sent: Monday, August 26, 2002 10:32 AM
To: 'steven.j.nelson@bt.com'; Jim.Brown@caselogic.com;
kip.palmer@verizon.net
Cc: ccielab@groupstudy.com
Subject: RE: I need FRTS help or review
Steven,
Now I'm not agree with You or maybe You right but CCO wrong :)
AR =96 K, CIR =96 K
Here again
http://www.cisco.com/warp/public/125/traffic_shaping_6151.html
Configure Be only if the Frame Relay CIR value is less than the AR.
So Be in your case should be "0".
And Bc+Be = 40000 bits in your case much more than AR/8 = 96000/8 =
12000
bits.
Depending on CIR it has to be =< 12000 - CIR*Tc (bits)
Dmitry
-----Original Message-----
From: steven.j.nelson@bt.com [mailto:steven.j.nelson@bt.com]
Sent: Monday, August 26, 2002 11:58 AM
To: Jim.Brown@caselogic.com; kip.palmer@verizon.net
Cc: ccielab@groupstudy.com
Subject: RE: I need FRTS help or review
All
Jim is correct in this one, his figures pan out as follows
CIR 96000
MINCIR 64000
BE 32000
BC 8000
TC 0.125Ms
So in 8 time slots (1 Second) he will transmit :-
0.125Ms 40000 (BC+BE)
0.125Ms 8000 (BC)
0.125Ms 8000 (BC)
0.125Ms 8000 (BC)
0.125Ms 8000 (BC)
0.125Ms 8000 (BC)
0.125Ms 8000 (BC)
0.125Ms 8000 (BC)
Which is equivalent to 96K per second.
And when no tokens are available then the MIN CIR will be met by the
8000 BC
* 8 = 64000
Thanks to Jim for this one.
Steve
-----Original Message-----
From: Jim Brown [mailto:Jim.Brown@caselogic.com]
Sent: 26 August 2002 15:24
To: 'kpalmer'
Cc: 'ccielab@groupstudy.com'
Subject: RE: I need FRTS help or review
After your e-mails I rethought my stance on FRTS. I did a little more
research and I believe my original configuration at the bottom of the
post
is the correct answer from a lab or testing context for a 96Kbps port
and
64Kbs contracted CIR.
map-class frame-relay TestShape
frame-relay cir 64000
frame-relay be 32000
frame-relay bc 8000
I'm basing this on a single new piece of information I turned-up. Check
the
Networkers 2002 CCIE Power Session, in their FRTS example, they
configure
the parameters exactly as I have described below.
I still stand by my original assessment of Cisco's CIR set to the
providers
CIR and Cisco's BE set to the difference between providers CIR and port
speed.
I'm posting this back to the list to hopefully open up discussion again.
-----Original Message-----
From: kpalmer [mailto:kip.palmer@verizon.net]
Sent: Sunday, August 25, 2002 8:27 PM
To: 'Jim Brown'
Subject: RE: I need FRTS help or review
Line speed | Access Rate | Port Speed
=======================================
What you bought from the Provider. Per DLCI.
Average Rate | configured CIR (not mincir)
=======================================
When Shaping 128 to 64, it's 64k, with Bc ='s the Average Rate of remote
64, /8.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Jim Brown
Sent: Sunday, August 25, 2002 1:04 PM
To: ccielab@groupstudy.com
Subject: I need FRTS help or review
Everything I have read about FRTS doesn't seem to clear up the use of
BE, BC, CIR, and MINCIR. I have been unable to locate a solid resource
explaining the concept with any finality.
I've read most of the relevant Usenet postings on Deja, watched the
threads on groupstudy, scoured CCO, and examined the QOS v1.0 course
material.
I will throw out my assumptions and let list members either verify or
shoot holes on my take of FRTS.
A few definitions up front:
AR is the Access Rate or Port Speed of the connection to the frame relay
cloud. This is the maximum number of bits that can be transmitted to the
cloud.
CIR is the Committed Information Rate. This is the maximum number of
bits the provider promises to transmit. Anything above the CIR and below
the access rate will have the DE bit marked and is eligible for
discard/drop during times of congestion.
Lets take a hypothetical circuit for instance, a port speed of 96Kbps
and a CIR of 64Kbps.
The way I read the documentation, in a Cisco configuration CIR should be
set to the actual provider CIR or 64000. The BE or burst excess should
be set to the difference between the access rate and the CIR. I think BE
should be set to 32000, the difference between 96 and 64.
Here is a brief sample config:
map-class frame-relay TestShape
frame-relay cir 64000
frame-relay be 32000
The map-class could then be applied to the frame map or the interface. I
was previously under the impression you would set the Cisco CIR to the
port speed and the minCIR to the provider contracted CIR. I don't think
this is really the case?
Here is an example:
map-class frame-relay TestShape
frame-relay cir 96000
frame-relay mincir 64000
Comments or suggestions? Is this wrong, why or why not?
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